The long term goal of this research program remains understanding nervous system function, as influenced by two widely distributed neuroactive molecules, GABA and N-acetylaspartylglutamate (NAAG). GABA and NAAG may participate in neuronal communication via receptors which are sensitive to both clinically significant and abused drugs. The immediate aims of the GABA/benzodiazepine research are: 1) To apply subunit specific, affinity purified antibodies, quantitative polymerase chain reaction and in situ hybridization to follow the transcription and expression of murine GABAA receptor subunits in the developing nervous system in vivo. 2) Apply similar methods to determine the influence of drugs, which inhibit neuronal activity, on GABAA receptor subunit expression and phosphorylation in cell culture. 3) To combine electrophysiology in cell culture with single cell PCR and in situ hybridization to correlate GABAA subunit expression with membrane conductance characteristics in response to the GABAA agonist, muscimol, as well as benzodiazepines and barbiturates. The significance of this work derives from the central role of the GABAA receptor in nervous system function and as the site of action of these sedative and anxiolytic drugs. The immediate aims of the NAAG research are: 1) To determine the influence of NAAG on synaptic release of GABA and acetylcholine in murine cortical and spinal cord cell cultures. 2) To determine the regional distribution of quisqualate-sensitive peptidase activity against NAAG in micropunched samples of brain tissue following lesion of projection pathways which express the peptide. 3) To determine the cellular distribution and release of NAAG in the embryonic nervous system as prelude to study of its role in development. The significance of this derives from the peptide's distribution, synaptic release and potential to act directly or via glutamate at neuronal receptors, including the phencyclidine-sensitive NMDA receptor.